Performance analysis of network-coded two-way dual-hop mixed FSO/RF systems

In this paper, a novel two-way relaying technique based on network coding is proposed to improve the throughput of dual-hop mixed free-space optics (FSO)/radio-frequency (RF) communication systems. We investigate the performance of the proposed systems over Gamma-Gamma atmospheric turbulence and Rice/Rayleigh channels. The effect of pointing error on FSO link is also considered in our analysis. Closed-form expressions for end-to-end outage probability and bit error rate are analytically formulated, taking into account the physical layer impairments from both FSO and RF links as well as the receiver noise. The numerical results show the feasibility of using network-coded two-way relaying in dual-hop mixed FSO/RF systems. In addition, the comparison between the magnitudes of negative impacts caused by FSO and RF links is discussed. Based on this comparison, the recommendation for locating the relay node is given so that better performance could be obtained.